Planning for the weather is a good way to make your trip to St. Petersburg relaxing and enjoyable, especially when you’re splurging. The hottest months are usually July and August with an average temp of 60°F, while the coldest months are January and February with an average of 24°F. The snowiest months in St. Petersburg are January, December, November, and February, with each month seeing an average of 13 inches of snowfall.